System and Method of Conditioning Recycled Air During Building Construction

ABSTRACT

A system and method that allows the interior air of a building to be conditioned during construction by the installed permanent HVAC systems, the system and method utilizing a portable, temporary, auxiliary air filtering and delivery system that provides filtered clean air to the HVAC system, with the installed air intakes and return air ductwork of the installed HVAC system being sealed such that all air to be conditioned by the HVAC system passes through the air filtering and delivery system, such that particulates and other detrimental airborne contaminants such as dust, fibers, etc. are removed prior to delivering the recycled air into the ductwork, filters and conditioning equipment of the permanent HVAC system. The auxiliary air filtering and delivery system is a combination of a filtering assembly, a fan assembly and delivery assembly, preferably provided in modular form.

BACKGROUND OF THE INVENTION

This invention relates generally to the field of building construction, and more particularly to the field of building construction wherein heating, ventilating and air-conditioning (HVAC) systems are installed in the building, as well as to the field of air filtering and delivery systems. Even more particularly, the invention relates to a system and methodology wherein air circulation and conditioning may be provided within a building during construction without dirtying the newly installed and clean ductwork and HVAC equipment.

The pace of construction today is much faster than it has been in the past, and continues to increase. General Contractors and Construction Managers (GC/CMs) are constantly pushing to finish jobs at a faster pace and ahead of schedule, as this not only allows for larger bonuses but makes a good impression on owners. There are certain issues that mechanical contractors face on nearly every job that conflict with a GC/CMs schedule. One such issue is the start-up of the HVAC equipment. The GC/CM wants to start the HVAC equipment up as soon as possible, as this allows for the entire building to be ‘dried out’. When the HVAC equipment is running, it dries the air in the space and allows flooring to be installed and finished, drywall to be dried in and completed, etc., which can save weeks or even months on the timeline of the project. Unfortunately, premature startup of the HVAC equipment early in the construction timeline can lead to significant problems. If the building is not properly sealed up and completely clean of airborne particulates (dirt, drywall dust, debris, etc.), the ductwork serving the HVAC equipment will not remain clean because of the airborne particles present in the space and the filters in the HVAC equipment may become excessively clogged, resulting in possible damage to the HVAC equipment. Early startup of the HVAC systems during ongoing construction will likely result in two major problems: (1) the ductwork must now be cleaned prior to occupancy, at a very expensive cost to the GC/CM, and (2) even after cleaning, a significant amount of particulates and contaminants will remain in the ductwork. In many facilities, such as hospitals, clean rooms, etc., a partially cleaned duct system will be unacceptable and a higher level of cleaning will be required to meet the standards or the previously installed ductwork will have to be replaced, which will be even more costly to the GC/CM.

It is an object of this invention to provide a system and method that alleviates the contamination issue of newly installed ductwork and HVAC systems awhile saving time and money on construction jobs. It is a further object to provide such a system and method that allows the interior air of the building to be recycled, cleaned and conditioned during construction while maintaining the cleanliness of the installed HVAC and ductwork systems, the system and method utilizing a portable, temporary, auxiliary air filtering and delivery system to deliver filtered clean air through the newly installed permanent ductwork and/or HVAC equipment. The system and method comprises various configurations and combinations of filters (both pre-filters such as MERV-13 and final filters such as 99.96% HEPA) ducted to a mixed flow, inline fan, such that airborne contaminants and particulates are removed from the inflow airstream and only clean air is passed into the return plenum of the installed HVAC equipment for conditioning and delivery into the building.

SUMMARY OF THE INVENTION

The invention in various embodiments comprises a system and method that recycles and conditions the interior air of a building under construction through the newly installed HVAC systems, the system and method utilizing a portable, temporary, auxiliary air filtering and delivery system that provides filtered clean air to the permanent HVAC unit, with the non-involved newly installed air intakes and return air ductwork being sealed such that all air to be conditioned by the HVAC system is drawn from a contained interior area of the building, passed through the auxiliary air filtering and delivery system, delivered into the HVAC unit and recycled into the contained area through the air outlets. The system and method may comprise various configurations and combinations of filters (both pre-filters such as MERV-13 and final filters such as 99.96% HEPA, for example) ducted to a mixed flow, inline fan, such that airborne contaminants and particulates are removed from the inflow airstream and only clean air is passed through the return plenum of the installed HVAC unit and ductwork into the building. The discharge from this fan preferably passes through a flow straightener and flexible ductwork directly into the return plenum air intake of the HVAC unit. The fan is operated by a controller that includes a variable frequency drive so that the airflow into the HVAC unit is adjusted to deliver the proper amount of airflow for the given HVAC system. In one embodiment, two high precision pressure sensors are provided in the air filtering and delivery system, one upstream of the fan and one downstream of the fan, such that once the required or desired airflow amount is input into a variable frequency drive controlling the fan, proper airflow is automatically maintained based on the output from these pressure sensors. As the filters become increasingly dirty and a change in differential pressure occurs, the variable frequency drive will increase speed to maintain the airflow set point. If the filters become too clogged, the auxiliary air filtering and delivery system is shut down and the filters are replaced. The entire system is preferably modular and portable, mounted on a series of rolling transport platforms or carts sized to allow passage through a standard 36 inch doorway, onto elevators, etc.

In alternative summary, the invention is A method of filtering and conditioning air in a building during construction having an operational HVAC system without contaminating the HVAC system, the HVAC system comprising an HVAC unit for conditioning air, an HVAC output plenum, an HVAC return plenum, room air intakes, room air outlets, and ductwork connecting the room air intakes to the HVAC return plenum and connecting the HVAC output plenum to the room air outlets, said method comprising the steps of: positioning an auxiliary air filtering and delivery system within the building under construction, said auxiliary air filtering and delivery system comprising a filtering assembly having filters, a fan assembly having a variable speed fan, and a delivery assembly; connecting said delivery assembly of said auxiliary air filtering and delivery system in fluid communication with the HVAC return plenum; sealing the room air intakes and other chosen physical openings to define a contained building area limiting the air to be filtered and conditioned; initiating said auxiliary air filtering and delivery system to draw air from said contained building area through said filtering assembly and initiating the HVAC unit; delivering said filtered air to said HVAC unit; conditioning said filtered air; and returning said filtered and conditioned air to said contained building area through the room air outlets. Furthermore, this method further comprising the steps of: monitoring air flow through the HVAC unit; and in response to a reduction in air flow through the HVAC unit, increasing the air flow speed of said variable speed fan of said fan assembly; further comprising the steps of: replacing said filters of said filtering assembly when said filters become clogged; further comprising the steps of: positioning an air flow sensor downstream or upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensor and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller; further comprising the steps of: positioning air flow sensors downstream and upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensors and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller; and/or further comprising the steps of: providing said auxiliary air filtering and delivery system as a modular system, wherein at least one of said filtering assembly, said fan assembly and said delivery assembly is separable from the others of said filtering assembly, said fan assembly and said delivery assembly; and combining said filtering assembly, said fan assembly and said delivery assembly within said building during construction prior to use.

Alternatively still, a method of filtering and conditioning air in a building during construction having an operational HVAC system without contaminating the HVAC system, the HVAC system comprising an HVAC unit for conditioning air, room air intakes, room air outlets, and ductwork connecting the room air intakes to the HVAC unit and connecting the HVAC unit to the room air outlets, said method comprising the steps of: positioning an auxiliary air filtering and delivery system within the building under construction, said auxiliary air filtering and delivery system comprising a filtering assembly having filters, a fan assembly having a variable speed fan, and a delivery assembly; connecting said auxiliary air filtering and delivery system in fluid communication with the HVAC unit; sealing the room air intakes and other chosen physical openings to define a contained building area limiting the air to be filtered and conditioned; initiating said auxiliary air filtering and delivery system to draw air from said contained building area through said filtering assembly and initiating the HVAC unit; delivering said filtered air to said HVAC unit; conditioning said filtered air; and returning said filtered and conditioned air to said contained building area through the room air outlets. Furthermore, this method further comprising the steps of: monitoring air flow through the HVAC unit; and in response to a reduction in air flow through the HVAC unit, increasing the air flow speed of said variable speed fan of said fan assembly; further comprising the steps of: replacing said filters of said filtering assembly when said filters become clogged; further comprising the steps of: positioning an air flow sensor downstream or upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensor and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller; further comprising the steps of: positioning air flow sensors downstream and upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensors and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller; and/or further comprising the steps of: providing said auxiliary air filtering and delivery system as a modular system, wherein at least one of said filtering assembly, said fan assembly and said delivery assembly is separable from the others of said filtering assembly, said fan assembly and said delivery assembly; and combining said filtering assembly, said fan assembly and said delivery assembly within said building during construction prior to use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a basic embodiment of the air filtering and delivery system.

FIG. 2 is a flow chart illustrating an embodiment of the method of the invention.

FIG. 3 is a schematic illustration of a typical HVAC system for a contained area within a building, the HVAC system having an HVAC unit for conditioning the air, air outlets, air intakes and ductwork connecting the components.

FIG. 4 is a schematic illustration of the embodiment shown in FIG. 3, wherein the air intakes have been sealed and air is drawn from the contained building area directly into the auxiliary air filtering and delivery system, cleaned and then delivered to the HVAC unit for conditioning and distribution through the air outlets.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the drawings, which are provided for descriptive and illustrative purposes and meant to be non-limiting as to the scope of the embodiments of the invention, the system and methodology will now be described.

In general, the invention is a system and method that allows the interior air of a building, while the building is still undergoing construction, to be cleaned and then conditioned by the newly installed, permanent HVAC units 90 of the building HVAC system, the HVAC system comprising room air outlets 91, room air intakes 92, ductwork 93 extending from the HVAC delivery outlet or plenum 94 of the HVAC unit 90 to the room air outlets 91, and ductwork 93 extending from the room air intakes 92 to the HVAC intake or plenum 94 of the HVAC unit 90. The ductwork 93 is typically composed of large aluminum conduits. Room air outlets 91 are typically slotted members mounted in ceilings or walls to cover the discharge openings of the ductwork 93. Room air intakes 92 are typically slotted members mounted in ceilings or walls to cover the return openings of the ductwork 93. Such HVAC systems are well known.

The system and method of the invention herein described utilizes a portable, temporary, auxiliary air filtering and delivery system or assembly 10 that draws in contaminated air from a contained building area, filters the air to remove contaminants, particulates, dust fibers, etc. and delivers the filtered clean air to the installed HVAC unit 90 for conditioning and return to the contained building area through the room air outlets 91, with the installed room air intakes 92 and return air ductwork 93 of the installed HVAC system being sealed or closed such that all air to be conditioned by the HVAC unit 90 is drawn into and passes through the auxiliary air filtering and delivery system 10 for removal of particulates and other detrimental airborne contaminants prior to delivering the now cleaned, filtered, recycled air into the filters and conditioning equipment of the permanent HVAC unit 90. The term “contained building area” as used herein refers to one or more rooms or sections of a building under construction wherein openings such as doors or windows, if present, are sealed or closed in addition to the room air intakes 92, such that only air from the contained building area is drawn into and recycled by the auxiliary air filtering and delivery system 10. With this system and method the contaminated air is filtered by the auxiliary air filtering and delivery system 10 and conditioned by the HVAC unit 90 without any of the contaminated air being drawn into the room air intakes 92 or return ductwork 93, such that the entire HVAC system remains in substantially pristine condition.

The system and method comprises in various possible configurations and combinations the provision of a an air filtering and delivery system 10 having a filtering assembly 20, a fan assembly 30 and a delivery assembly 40. The assemblies 20/30/40 may be provided as a single integrated unit, but more preferably two or more of the assemblies 20/30/40 are provided as separable modular units that are combined prior to use to form the complete auxiliary air filtering and delivery system 10. As shown in FIG. 1, the modular units may be mounted onto transport platforms 11, such that each modular unit occupies a small footprint relative to the complete system 10, thereby allowing the units to be more easily positioned with the building under construction, such as by transporting the modular units by forklift or by providing wheels 12. Most preferably, each modular unit is sized such that it can easily pass through doorways or into elevators.

The filtering assembly 20 comprises a plurality of removable, replaceable filters, with the filters preferably comprising filters of differing characteristics, such as pre-filters 21 and final or secondary filters 22. In this manner the pre-filters 21, such as for example MERV 13 filters, are chosen to trap the larger airborne particulates drawn into the filter inlets or intakes 25, while the final or secondary filters 22, such as for example 99.96% HEPA filters, are chosen to trap the smaller airborne particulates. The filtered clean air then passes through a filter conduit 23 into the fan assembly 30. In modular systems 10, the filter assembly 20 is provided with a connecting member or flange 24 that mates with a connecting member or flange 31 on the intake side of the fan assembly 30. The filtering assembly 20, pre-filters 21 and secondary filters 22 are sized such that air in equivalent amount to the amount of return air normally drawn from the now-sealed room air intakes 92 within the contained building area can be drawn into the auxiliary air filtering and delivery system 10 and passed into the HVAC unit 90. The filtering assembly 20 may be structured to draw in air from multiple directions. The filtering assembly 20 of the auxiliary air filtering and delivery system 10 may be positioned and exposed within the contained building area, or may be connected by one or more conduits or sealing members, such as plastic sheeting, to one or more physical openings, such as doors or windows, leading into the contained building area.

The fan assembly 30 comprises a fan 30, preferably of a mixed flow, inline type, that draws the dirty building air from the contained building area through the filtering assembly 20 and then passes the clean, filtered air into the delivery assembly 40 for delivery to the return plenum 95 of the installed HVAC unit 90, the delivery system 40 in modular embodiments having a connecting member or flange 43 that is mated to a fan connecting flange 31 on the discharge side of the fan 34. The delivery assembly 40 preferably comprises an air flow conduit 41 that comprises an air flow straightener mechanism. Preferably the discharge from the fan 34 passes through a flexible conduit 42 directly into the return plenum of the HVAC system, the flexible conduit 42 being joined to the airflow conduit 41 by connecting members or flanges 43. Alternatively, the flexible conduit 42 may be connected into an unsealed room air intake 92 or a portion of the return ductwork 93 for delivery to the HVAC unit 90, since the air being recycled is now clean of contaminants.

It is critical that proper airflow volume is provided to the HVAC equipment 90 by the auxiliary air filtering and delivery system 10 to preclude damaging or otherwise adversely affecting the installed HVAC unit 90. To accomplish this, the fan 30 is a preferably a variable speed fan operated by a fan controller 32, which may include for example a variable frequency drive system, connected to at least one pressure or airflow sensor 33, such that fan speed may be varied as required to maintain airflow within the desired parameters for a given HVAC unit 90 as airflow through the filters 21/22 is reduced due to the increase in trapped contaminants and particulates over time. In the embodiment as shown in FIG. 1, two high precision pressure or airflow sensors 33 are provided in the auxiliary air filtering and delivery system 10, one upstream of the fan 30 and one downstream of the fan 30, such that with the required or desired airflow parameters for a given HVAC unit 90 input into the processor of the fan controller 32, proper airflow is automatically maintained based on the output from these pressure sensors 33. Alternatively, in some embodiments, fan 30 may have a built-in sensor, e.g., a piezo ring, that provides information on a pressure rise across the fan 30 to the fan controller 32, thus negating the need for a downstream airflow sensor 33. As the filters 21/22 become dirty and a change in differential pressure occurs, the fan controller 32 will increase fan speed to maintain the airflow set point. The auxiliary air filtering and delivery system 10 will preferably be capable of a selectable airflow range of approximately 1,000 cfm-15,000 cfm. When the filters 21/22 become so clogged that an increase in fan speed is insufficient to maintain proper airflow, the air filtering and delivery system 10 is stopped and the filters 21/22 are replaced as needed.

Various embodiments of the auxiliary air filtering and delivery system 10 are possible and contemplated. In one possible embodiment, a single auxiliary air filtering and delivery system 10 provides clean air to the single HVAC intake or return plenum 95 of an HVAC unit 90. In another embodiment, a single auxiliary air filtering and delivery system 10 delivers clean air to multiple ductwork 93 for the HVAC unit 90. This may be due to size limitations in the room, size limitations of the ductwork, etc. In another embodiment, a single auxiliary air filtering and delivery system 10 delivers clean air to multiple HVAC units 90, such as by providing for multiple flexible ductwork members 42 in a manifold type arrangement. In another embodiment, multiple auxiliary air filtering and delivery systems 10 deliver clean air to a single HVAC unit 90, which may be required due to the HVAC unit 90 having a larger capacity requirement than that of a single auxiliary air filtering and delivery system 10. In another embodiment, multiple auxiliary air filtering and delivery systems 10 deliver clean air to multiple HVAC units 90.

The auxiliary air filtering and delivery system 10 may comprise multiple air intakes 25, which may simply be exposed in different directions or which may be connected to a system of ducts or conduits that connect to various spaces within the building to pull airflow from multiple locations within the contained building area for pressure maintenance, uniform/non-uniform return airflow, etc. Various filter combinations and types may be utilized.

The size of the auxiliary air filtering and delivery system 10 and/or the modular units comprising an auxiliary air filtering and delivery system 10 may vary. For example, for an auxiliary air filtering and delivery system 10 and/or the modular units capable of fitting through a standard-size door, the fan assembly 30 may be limited to a fan 30 delivering up to 15,000 CFM. Larger auxiliary air filtering and delivery system 10 and/or the modular units capable of fitting through a standard-size double door may have a capacity range of 5,000 CFM to 60,000 CFM, for example.

The methodology of the invention is illustrated in the flow chart of FIG. 2. Prior to completing construction of a building in which a functioning HVAC system has already been installed, an auxiliary air filtering and delivery system 10 as described is positioned within the building, with the joining of modular units if required to create a functioning auxiliary air filtering and delivery system 10 (step 100). The auxiliary air filtering and delivery system 10 is then connected in fluid communicating manner to the intake or return plenum 95 of the installed HVAC unit 90 for delivery of filtered air (step 101). The auxiliary air filtering and delivery system 10 may be positioned within the contained building area or may be connected by suitable conduits to a physical opening, such as a door or window, leading into the contained building area. The room air intakes 92 of the HVAC system and any physical room openings are then sealed so that no unfiltered air from within or outside of the contained building area will be delivered through the room air intakes 92 or return ductwork 93 to the HVAC unit 90 for conditioning, thereby defining the contained building area in which the air is to be recycled (step 102). The auxiliary air filtering and delivery system 10 is then initiated to draw and filter air from the contained building area and then deliver the cleaned air to the HVAC unit 90, the HVAC unit 90 also being initiated to condition, i.e., cool or heat, the building air received from the auxiliary air filtering and delivery system 10 (step 103). In this manner air from the contained building area is continuously recycled, the air being cleaned of airborne particulates by the auxiliary air filtering and delivery system 10 such that the new HVAC system is not sullied by the airborne contaminants and will be in substantially pristine condition when the building construction is completed. In addition, the HVAC unit 90 dehumidifies the recycled air, thereby shortening dry times for drywall or paint curing. The airflow through the auxiliary air filtering and delivery system 10 delivered to the installed HVAC unit 90 is controlled by automatic adjustment of the speed of the fan 30 as required to maintain the proper rate, amount or volume of air flow (step 104). When required because of excessive clogging of the filters 21/22, the filters 21/22 are removed and replaced as required to maintain proper airflow into the HVAC unit 90 (step 105).

It is understood and contemplated that equivalents and substitutions for certain elements or steps set forth above may be obvious to those of skill in the art, and therefore the true scope and definition of the invention is to be as set forth in the following claims. 

We claim:
 1. A method of filtering and conditioning air in a building during construction having an operational HVAC system without contaminating the HVAC system, the HVAC system comprising an HVAC unit for conditioning air, an HVAC output plenum, an HVAC return plenum, room air intakes, room air outlets, and ductwork connecting the room air intakes to the HVAC return plenum and connecting the HVAC output plenum to the room air outlets, said method comprising the steps of: positioning an auxiliary air filtering and delivery system within the building under construction, said auxiliary air filtering and delivery system comprising a filtering assembly having filters, a fan assembly having a variable speed fan, and a delivery assembly; connecting said delivery assembly of said auxiliary air filtering and delivery system in fluid communication with the HVAC return plenum; sealing the room air intakes and other chosen physical openings to define a contained building area limiting the air to be filtered and conditioned; initiating said auxiliary air filtering and delivery system to draw air from said contained building area through said filtering assembly and initiating the HVAC unit; delivering said filtered air to said HVAC unit; conditioning said filtered air; and returning said filtered and conditioned air to said contained building area through the room air outlets.
 2. The method of claim 1, further comprising the steps of: monitoring air flow through the HVAC unit; and in response to a reduction in air flow through the HVAC unit, increasing the air flow speed of said variable speed fan of said fan assembly.
 3. The method of claim 2, further comprising the steps of: replacing said filters of said filtering assembly when said filters become clogged.
 4. The method of claim 2, further comprising the steps of: positioning an air flow sensor downstream or upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensor and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller.
 5. The method of claim 2, further comprising the steps of: positioning air flow sensors downstream and upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensors and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller.
 6. The method of claim 1, further comprising the steps of: providing said auxiliary air filtering and delivery system as a modular system, wherein at least one of said filtering assembly, said fan assembly and said delivery assembly is separable from the others of said filtering assembly, said fan assembly and said delivery assembly; and combining said filtering assembly, said fan assembly and said delivery assembly within said building during construction prior to use.
 7. A method of filtering and conditioning air in a building during construction having an operational HVAC system without contaminating the HVAC system, the HVAC system comprising an HVAC unit for conditioning air, room air intakes, room air outlets, and ductwork connecting the room air intakes to the HVAC unit and connecting the HVAC unit to the room air outlets, said method comprising the steps of: positioning an auxiliary air filtering and delivery system within the building under construction, said auxiliary air filtering and delivery system comprising a filtering assembly having filters, a fan assembly having a variable speed fan, and a delivery assembly; connecting said auxiliary air filtering and delivery system in fluid communication with the HVAC unit; sealing the room air intakes and other chosen physical openings to define a contained building area limiting the air to be filtered and conditioned; initiating said auxiliary air filtering and delivery system to draw air from said contained building area through said filtering assembly and initiating the HVAC unit; delivering said filtered air to said HVAC unit; conditioning said filtered air; and returning said filtered and conditioned air to said contained building area through the room air outlets.
 8. The method of claim 7, further comprising the steps of: monitoring air flow through the HVAC unit; and in response to a reduction in air flow through the HVAC unit, increasing the air flow speed of said variable speed fan of said fan assembly.
 9. The method of claim 8, further comprising the steps of: replacing said filters of said filtering assembly when said filters become clogged.
 10. The method of claim 8, further comprising the steps of: positioning an air flow sensor downstream or upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensor and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller.
 11. The method of claim 8, further comprising the steps of: positioning air flow sensors downstream and upstream of said variable speed fan; and providing a fan controller in communication with said air flow sensors and variable speed fan, wherein the sir flow speed of said fan is automatically controlled by said fan controller.
 12. The method of claim 7, further comprising the steps of: providing said auxiliary air filtering and delivery system as a modular system, wherein at least one of said filtering assembly, said fan assembly and said delivery assembly is separable from the others of said filtering assembly, said fan assembly and said delivery assembly; and combining said filtering assembly, said fan assembly and said delivery assembly within said building during construction prior to use. 